1902] A MORPHOLOGICAL STUDY OF ASCLEPIADACEAE 411 



8. Gager, C. S., The development of the pollinium and sperm-cells in 



Asclepias Corniiti, Ann. Botany 16 : 123-148.//. 7. IQ02. 



g. GuiGNARD, L., Sur les anthdrozoides et la double copulation sexuelle 



chez les v^g^taux angiospermes. Compt. Rend. 128 : 864-871. 1899. 



10. ScHACHT, H., Das Mikroskop. pp. 150-156. pL 2, and Jig. 11, pL j. 



Berlin. 1851. 



11. Schumann, K., Engler and Prantl's Nat. Pflanzenfam. 4* : 238. 1895. 



12. Smith, R. W., The structure and development of the sporophylls and 



sporangia of Isoetes. Box, Gaz. 29 : 225-258, 323-346. pis, /j-20 

 {^tcjigs, 2j and 24 on pi. 14.). 1900. 



13. Stephens, W. C, The behavior of kinoplasm and nucleolus in the 



division of the pollen mother cells of Asclepias Cornuti. Kansas Univ. 

 Quart. 7 : 77-86.//. j. 1898. 



14. Strasburger, E., Einige Bemerkungen zu der PoUenbildung bei As- 



clepias. Ber Deutsch. Bot. Gesell. 19 : 450-461. j!^/. 24., 1901- 



15. Treub, M., Sur les Casuarin^es et leur place dans le systeme naturel. 



Ann. Jard. Bot. Buitenzorg 10 : 145-231. pis, 12-ji, 189I. 



16. VoCHTiNG, H,, Zur Physiologic der Knollengewachse. Jahrb. Wiss. Bot. 



34 : i-i48,//j. 7-5, 1900. 



EXPLANATION OF PLATES XIII-XV. 



All drawings X 23 or more were made with a camera lucida. The 



lenses used were Zeiss compensating oculars in combination with Leitz dry 



lenses, a Zeiss dry achromatic adjustable, or a Zeiss 1^2 apochromatic oil. 

 The original drawings, for which the magnifications are indicated, are twice 



as large as the reproduction. 



Asclepias tub eras a. 



Fig. I. Longitudinal section through stem tip showing terminal umbel ; £, 



glands ; partly diagrammatic ; X 30. 

 Fig. 2. Hair from the epidermis of the calyx ; X 390. 

 Figs. 3-4. Glands on the adaxial surface of the calyx ; /, petal ; 5, sepal ; X 



555- 



Fig. 5. Top view of flower with all its organs removed except the sepals ; s, 



sepal ; g, gland ; /, .where petals have been cut ; shows position of 



glands; X 48. 



Asclepias Sullivantii, 



Fig. 6. Part of longitudinal section through flower showing three glands in 



radial relation ; 5, sepal ; /, petal ; *, bundle ; X 48. 



Asclepias Cornuti. 



Fig. 7. Basal portion of bract from umbel showing glands on adaxial surface ; 



X 48, 



1 

 4 



